Improvement in steam-generators



space above it.

UNITED STATES PATENT OEEIoEo THOMAS MAIN, OF GREEN PONT, NEW YORK.

IM PROVEM ENT IN STEAM-GENERATO RS.

Specication forming part of Letters Patent' No. 59,424, dated November6, 1866.

To all whom it may concern:

Be it known that I, THOMAS MAIN, of Green Point, in the county of Kings,State of New York, have invented a new and useful Improvement inSteam-Boilers; and I do hereby declare that the following is a full,clear, and exact description thereof.

This invention consists in combining the advantages of a horizontalboiler (which shall have a water-space or bridge-wall in the furnace anda combination chamber) with an upright tubular boiler, and also inproviding a perforated pipe, and locating it so that it shallreceive'and discharge the steam ina superheated state.

To enable others skilled in the artto make and use my invention, I willproceed to describe it, reference being had to the accompanyingdrawings, forming part of this specification, and to the letters ofreference marked therein.

Figure l represents a top View, partly sectional, as at h, with the hoodand chimney removed. Fig. 2 is a longitudinal sectional elevationthrough the line x a, Fig. l; and Fig. 3 is a front elevation of theboiler.

Similar letters of reference indicate like parts.

A represents the furnace of a horizontal locomotive-boiler, and A thewater and steam B represents the upright tubular portion of the boiler.b represents' the shell. e is the water-line. a is the crownsheet or tipof the furnace. O is a waterspace or bridge-wall, forming the back partof the furnace. D is the combustion-chamber, and f represents the tubesof the upright part. P is the dry pipe, from which the steam isdischarged, aud h the water-spaces of the boiler, surrounding thefurnace or fire-box and tubes of the upright portion.

The fuel rests upon the grate-bars g, and the products of combustion, intheir passage to the nue-tubes of the upright part, pass over thewater-space C into the combustion-chamber D. This chamber is formed -bythe space between the bridge-wall or water-space C and the shell orwater-space of the upright tubular portion of the boiler, and extendsdown and under the said tubular portion.

The products of combustion pass through the large iiue G over thebridge-wall at a very high temperature.` Inl this condition they arecompelled to descend, and are re-v is in open communication with thewaterspaces which surround the furnace. It is curved upward at the sidesof the furnace, as seen at k, in Fig. 3. This curved portion is alsoopen to those water-spaces, like the lower part, and it is curved forthe purpose of allowing a free circulation of water and a free escapefor the globules of steam formed in it.

The sides of the fire-box or furnace are cut away where this bridge-wallis situated, thus allowing a free circulation of water through it. It isfirmly riveted to the sides of the furnace, its lower edge resting uponthe common foundation. This water-space or bridge-wall O, althoughdescribed as containing water, or as being a water-wall, may beconstructed of brick or any other incombustible material, and in thatcase the sides of the furnace would be left whole.

The furnace and horizontal portion of the boiler is lapped on and rmlysecured to the upright tubular portion, the lower surfaces or bottom ofeach being on a level and resting on a common foundation. The upper andlower heads of this tubular boiler are secured to the shell in the usualmanner, and the tubes are distributed over the entire diameter orsurface of the heads at suitable distances from leach other and from theshell, with the exception of a space sufficiently large to admit the dryor discharge pipe l?. These tubes have free communication with the waterof the horizontal portion of the boiler over the furnace, and aresurrounded with water up to the Waterline e, as seen in Fig. 2.

The heated air and products of combustion pass from thecombustion-chamber upward through the tubes in their course to thechimney I. The upper portion of these tubes extend above the water-linethrough the steamspace, their surfaces being at a high temperature fromthe products of combustion.

The discharge-pipe P is placed in the space left for it among thesetubes, but near their top, and is supported from the head or tubesheet,and also at the point where it passes through the shell. It extends fromthe outside through the shell and runs nearly across the whole diameterof the tubular boiler. That portion of it which lies inside, among thetubes, is perforated through its upper surface, nearly its whole length,with holes sufcient-ly large for the admission of the steam. When thispipe is discharging there is a rush of steam to it from every direction,and the steam, coming in contact with and impinging against the heatedsurfaces of the tubes, becomes superheated, and all watery particlesheld in suspension are at once converted into steam.

t The importance of this arrangement will at once be understood by anyone at all conversant with the use of steam, and the advantage gained inusing dry steam-thatis, steam which holds no watery particles insuspension-can scarcely be overrated.

H is the hood supporting the chimney I. There may be doors in this hood(which sits upon the top of the boiler directly over the tubes) to allowthe tubes to be scraped or cleaned when necessary.

d is a door into the lower part of the combustionchamber, which allowsany soot or ashes which may accumulate there to be removed. T is a doorinto the ash-pit S under the grate, and E is the foundation of theboiler. R is the furnace-door, and 19 is amanhole into the horizontalboiler over the furnace.

Hand-holes may be introduced through the shell int-o the water-spaces toallow any sediment which maybe precipitated to be removed.

The furnace can be made of any size to suit any kind of fuel, and theconstruction of the whole boiler is such that very little bracing isrequired.

The water is free to circulate around and between the tubes f and aroundthe radiating surfaces of the furnace and combustion-chamber, the lowerplate, i, of the water-spaces being lower than the grate-bars.

The course of the products of combustion is indicated in colors, and iseasily traced.

What I claim as new, and desire to secure by Letters Patent, is-

1. The horizontal chamber A, combustionchamber D, portion B, providedwith vertical tubes, and water-space or bridge-wall C, when combined andarranged substantially as herein shown and described.

2. The arrangement of the perforated discharge-pipe P with the tubes ofa vertical boiler, substantially as herein shown and described, for thepurpose of receiving and discharging the steam in a superheatcd state,as set forth.

THOMAS MAIN.

Witnesses WM. F. MGNAMARA, ALEX. F. ROBERTS.

